Grid leak and condenser



Feb. 18, 1939. w. E. woons GRID LEAK AND CONDENSER Filed April 23, 1925 Patented Feb. 18, 1930 UNITED STATES PATENT OFFICE WILLIAM E. WOODS, OF ST. LOUIS, MISSOURI, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO TRAV-LER MANUFACTURING CORPORATION, OF ST. LOUIS, MISSOURI, A COR- PORATION OF ILLINOIS GRID LEAK AND CONDENSER Application filed April 23,1925.

This invention relates to radio appliances and more particularly to condensers for use in the grid circuit and which may have com bined therewith the so-called grid leak.

One of the objects of this invention is to provide a condenser which shall be simple in construction and durable in service.

Another object of this invention is to pro- Vide a condenser which may have incorporated therewith a suitable high resistance grid leak.

Further objects will appear from the detail description taken in connection with the accompanying drawing, in which:

Figure 1 is a plan view of a condenser embodying this invention;

Figure 2 is a section on line 2-2, Figure 1;

Figure 3 is a view similar to Figure 1, but showing the cover plate and insulating plate removed so as to expose the condenser plates; and

Figure 4 is a view similar to Figure 3, but showing the grid leak.

Referring to the accompanying drawing, the condenser comprises a series of sheet metal plates or discs 1 each provided with a radially extending arm 2 and having a central perforation 3. These plates may be formed by punching from sheet metal which is heavy enough to provide stiffness for the arms 2. The ordinary metal foil has not suflicient inherent stifiness to make the arms 2 rigid. The arms 2 are each provided w th a terminal having a perforation 4 to receive a suitable fastener. The condenser plates 1 are arranged in two sets and are assembled as illustrated in Figure 2 with the plates of different sets alternating. These plates are insulated from each other by means of mica or other suitable insulating plates 5 which are also centrally perforated, but whose perforation is smaller than that of the plates 1. In assembling the plates, a mica plate is inserted between each two metal plates so that the insulating plates and metal plates alternate in the assembly illustrated in Figure 2. The insulating plates may also be made of larger diameter than the metal plates 1 so as to provide a margin about the outside of the plates 1, thereby providing additional creep- Serial No. 25,227.

age distance and therefore more eifective insulation. The perforation 6 in the center of the insulating disc is adapted to receive a fastener 7 in the form of a clamping screw which passes through the perforations 6 and also through central perforations in a pair of clamping end plates 12 so as to clamp the entire series of discs together. The perforations 3 in the condenser plates being larger than those in the insulating plates, a clearance space is provided about the fastener 7 so as to avoid contact therewith by the plates 1.

V In order to provide a grid leak, a plate of paper or other suitable material may be punched out to the same shape as that of the plates 1. This plate may then be coated on one side with a coating 8 of india ink or other suitable material adapted to provide a high resistance leakage path. This plate may then be'inserted with its blackened face in contact with a condenser plate of one set and its arm 9 extending in cooperative relation with the arms 2 of the other set. The arms of each set of plates are brought into alinement so that a clamping screw 15 may be passed through the perforations 4 of each set so as to clamp the same together. The arm 9 is provided with a similar perforation l0 and the clamps ing screw passed therethrough so as to connect said arm 9 with the arms 2 of the corresponding set of plates.

A convenient and efiective condenser is thus provided and one which is simple and cheap to construct. The sheet metal plates 1 being provided with rigid arms 2 which may be turned to various relative positions about the clamping screw 7, the distance between the terminal opening 4 may be adjusted so that the condenser may be arranged for connection to the terminals of a radio set. The coating 8 being in contact with a condenser plate of one set at its central portion and with those of the other set at the end of the arm 9 provides a simple and effective high resistance leakage path. The entire set is of simple construction and is easily and quickly repaired or extensions made thereto by the addition of additional plates.

It is obvious that various changes may be made in details of construction without dea parting from the spirit of this invention; it

is, therefore, to be understood that this invention is not to be limited to the specific details shown and described.

Having thus described the invention, what is claimed is: V

1. A grid condenser and leak, comprising, a series of conducting discs each of which has a-radiatingarm, separated by alternate insulating discs and the whole clamped to gather to form a unitary structure, the arms of each set of alternate conducting discs 'being connected together and provided With a terminal, and a similarly formed high-resistance disc incorporated in said structure so as to contact with a conductingdisc of one of said sets and having its arm connected to the terminal of the other set. V a

2. A gridcondenser and leak, comprising,

a series of perforated conducting discs each of which has a radiating arm, separated by alternate insulating discs and the whole clamped together by a fastener thruthe perforations thereof to form a unitary, structure, the arms of each set of alternate conducting discs being connected together and provided with a terminal, and a similarly formed high-resistance disc incorporated in said structure so as to contact with a conducting disc of one of said sets and having its arm connected to the terminals of the other set, 3. A; grid condenser and leak, comprising, a seriesof conducting discs each of which has a radiating arm, separated by alternate insulatingkdiscs and the whole clamped together to form a unitary structure, the arms of each setof alternate conducting discs being connected together and provided with a terminal, and a similarly formed insulating disc coated to provide a high resistance and incorporated in said structure with its coating in contact with a conducting disc of one of said sets and having its arm connected to the terminal of the other set. 4. A grid condenser and leak comprising, a series of conducting discs each of which has a radiating arm, separated by alternate insulating discs and the whole rotatively clamped together to form a unitary structure, the arms of each set of alternate conducting discs being connected together andprovided with a terminal, and a similarly formed highrcsistance disc incorporated in saidstructure so as to contact with a conducting disc of one of said sets and having its arm connected to the terminal of the other set, whereby said setsmay-be rotated relatively to one another in 1order to vary the spacing of said termina s.

In testimony whereof I afix my signature this 13th day of April, 1925.

1 .WILLIAM E. WOODS. 

